Recording a square: hectads, tetrads, monads, DINTY…

Suggestions on how to record an area

In general, the B.S.B.I. urges recorders to make lists within individual monads (see below for explanations on terms). However, tetrads are still very useful units for rationalising one’s day in the field.

A good plan, having chosen (or been allocated) a tetrad, is to judge from the map, or from experience, or by viewing on the ground, which monad is likely to be the most productive in that tetrad (productivity being measured in terms of maximising one’s final count within the available time constraints). Perhaps the chosen monad promises to supply the largest range of habitats, for instance, but other factors such as accessibility, footpaths, open access land vs. private land when the owner is unknown, etc., also will play a part.

Spend a good proportion of your available time in the chosen monad. If your time is short, then aim to move into other monads in that tetrad, but just make a separate list of the additional species you encounter: this will add to the tetrad-list. If you have more time, then make fuller lists, but be aware that much time spent in a small area re-recording the abundant species may be less valuable than covering more ground in the new monad, perhaps revealing new habitats. (‘Covering the ground’ also enables you to get a better sense of just what is available in that tetrad, so that other areas can be targeted if or when you revisit, perhaps at a different season.)


A hectad is a 10km × 10km square of the Ordnance Survey National Grid.

These are the hectad designations for the county:


A tetrad is a 2km × 2km square of the Ordnance Survey National Grid. Tetrads are much-used recording units in field-botany and for other classes. A Flora of Cumbria uses tetrad dots on its distribution maps, as do many other similar works.

We previously designated a particular tetrad by means of the grid-reference of its south-west corner, so e.g. the blue tetrad in Hectad NY45, below, would be ‘NY4658’.


However, this is ambigous, since ‘NY4658’ also refers to a monad, which is a 1km × 1km square, marked as a green square below. To avoid ambiguity, the ‘DINTY‘ designation is now used, and this is explained next (a downloadable image).

DINTY explanation

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